/*
Copyright (C) 2015-2019 The University of Notre Dame
This software is distributed under the GNU General Public License.
See the file LICENSE for details.
*/

#include "list.h"

void list_push_head(struct list *list, struct list_node *node)
{
	node->next = list->head;
	node->prev = 0;
	node->priority = 0;
	if(list->head)
		list->head->prev = node;
	list->head = node;
	if(!list->tail)
		list->tail = node;
	node->list = list;
	list->size++;
}

void list_push_tail(struct list *list, struct list_node *node)
{
	node->prev = list->tail;
	node->next = 0;
	node->priority = 0;
	if(list->tail)
		list->tail->next = node;
	list->tail = node;
	if(!list->head)
		list->head = node;
	node->list = list;
	list->size++;
}

void list_push_priority(struct list *list, struct list_node *node, int pri)
{
	struct list_node *n;
	int i = 0;
	if(!list->head) {
		list_push_head(list, node);
		return;
	}
	for(n = list->head; n; n = n->next) {
		if(pri > n->priority || i > 5000) {
			node->next = n;
			node->prev = n->prev;
			node->priority = pri;
			if(n->prev) {
				n->prev->next = node;
			} else {
				list->head = node;
			}
			n->prev = node;
			node->list = list;
			list->size++;
			return;
		}
		i++;
	}
	list_push_tail(list, node);
}

struct list_node *list_pop_head(struct list *list)
{
	struct list_node *result = list->head;
	if(list->head) {
		list->head = list->head->next;
		if(list->head)
			list->head->prev = 0;
		if(!list->head)
			list->tail = 0;
		result->next = result->prev = 0;
		result->list = 0;
		list->size--;
	}
	return result;
}

struct list_node *list_pop_tail(struct list *list)
{
	struct list_node *result = list->tail;
	if(list->tail) {
		list->tail = list->tail->prev;
		if(list->tail)
			list->tail->next = 0;
		if(!list->tail)
			list->head = 0;
		result->next = result->prev = 0;
		result->list = 0;
		list->size--;
	}
	return result;
}

void list_remove(struct list_node *node)
{
	if(!node->list)
		return;
	if(node->list->head == node) {
		list_pop_head(node->list);
		return;
	}
	if(node->list->tail == node) {
		list_pop_tail(node->list);
		return;
	}
	node->next->prev = node->prev;
	node->prev->next = node->next;
	node->next = node->prev = 0;
	node->list = 0;
	node->list->size--;
}

int list_size( struct list *list )
{
	return list->size;
}